scholarly journals EXPERIMENTAL STUDY OF SOLAR CHIMNEY PERFORMANCE FOR PASSIVE HEATING

2018 ◽  
Vol 18 (3) ◽  
pp. 375-388
Author(s):  
Majid H Majeed ◽  
Ibrahim S Resen
Keyword(s):  
Experimental Study ◽  
Experimental Investigation ◽  
Vertical Wall ◽  
Air Gap ◽  
Passive Heating ◽  
Front Side ◽  
Solar Chimney ◽  
Constant Height ◽  
Gap Width ◽  
Indoor And Outdoor

An experimental investigation on solar chimney used for heating under climate of Iraqis carried out. Experiments were conducted on the chimney installed on vertical wall withabsorber plate placed at the front side of the air gap. The solar chimney attached to room ofdimensions (2.5×1.29×1.07) m. The chimney is studied to measure the effect of the air gapwidth with constant height of (1.07 m). Three widths are tested, namely, 0.2 m, 0.3 m and0.4 m. The experimental results showed that the solar chimney can achieve about (13 °C)difference in temperature between indoor and outdoor as well as it gives acceptabledifference in partial cloudy days. The results also indicated that the best performance ofsolar chimney is with 0.3m air gap width.

Effects of wall proximity on the airflow in a vertical solar chimney for natural ventilation of dwellings

2020 ◽  
Vol 44 (3) ◽  
pp. 225-250
Author(s):  
Y Quoc Nguyen ◽  
John Craig Wells
Keyword(s):  
Heat Source ◽  
Natural Ventilation ◽  
Vertical Wall ◽  
Air Gap ◽  
Horizontal Plate ◽  
Solar Chimney ◽  
Horizontal Wall ◽  
Induced Flow ◽  
Air Channel ◽  
Wall Proximity

This study investigates performance of a vertical solar chimney, which absorbs solar energy and induces airflow for natural ventilation and cooling of dwellings, under effects of walls neighboring to its air channel. A computational fluid dynamics model was developed to predict induced flow rate and thermal efficiency of a vertical solar chimney with four types of nearby walls: a vertical wall to which the solar chimney was attached, a horizontal plate above the outlet of the air channel, a horizontal plate, and a horizontal wall below the inlet of the air channel. Examined factors included the heat flux in the air channel, the chimney height, the air gap, the distance of the walls, and the location of the heat source in the air channel. The results showed that effects of the wall proximity were modulated by the location of the heat source and the ratio G/ H between the air gap and the chimney height. Particularly, performance of the chimney was enhanced when the heat source was on the opposite side of the vertical wall and when G/ H was large.

scholarly journals Prediction of Indoor Air Circulation of Residential Room with Adaptation of Solar Chimney Using Numerical Technique

2019 ◽  
Vol 8 (11) ◽  
pp. 4110-4116
Keyword(s):  
Air Temperature ◽  
Cooling System ◽  
Residential Buildings ◽  
Numerical Technique ◽  
Electrical Power ◽  
Air Gap ◽  
Solar Chimney ◽  
Heating And Cooling ◽  
Gap Width ◽  
Ventilation Velocity

With the exponential increase in consumption of electrical power during the summer season by household, there is a great need for households to withhold sustainability. To maintain the temperature of the household a passive heating and cooling system is used i.e. Solar Chimney. Ventilation, through a natural convection process, is gaining a lot of attention to be an alternative technique for mechanical air conditioning ventilation because of its reduced power usage when compared to the external cooling devices used in residential buildings of hot regions. The present study, involve solar chimney of horizontal and vertical designs in comparison with different width and height. The following paper studies the effect of a solar chimney on the indoor thermal behavior using Numerical Technique for a prototype of a residential room. The performance on the ventilation velocity and air temperature operation inside the room with varying air gap width is studied based on multiple numerical analysis solutions. The present study deals with two different architectures of a two dimensional model and results have shown that the ventilation velocity has increased to 0.017626444 kg/s and operative air temperature has been decreased by 7.26ºC for the vertical model while the horizontal model has shown a mass flow rate of 0.018027636 kg/s and a temperature decrease of 9.15ºC. The most efficient chimney was found to be model 7 which is horizontal solar chimney 3 with an air gap width of 0.05625m and a height of 0.3175 m, when compared to the other models from model number one to six.

scholarly journals The effect of using ribbed absorber plates on enhancing the heat transfer of solar chimneys

2021 ◽  
Vol 23 (07) ◽  
pp. 1431-1444
Author(s):  
Mohammed N. Jihad ◽  
◽  
Nabil J. Yasin ◽  
Kadhum A. Jehhef ◽  
◽  
...  
Keyword(s):  
Inclination Angle ◽  
Air Gap ◽  
Test Model ◽  
Solar Chimney ◽  
Absorber Plate ◽  
Ansys Fluent ◽  
Solar Radiation Intensity ◽  
Test Models ◽  
Inclination Angles ◽  
Gap Width

Under different geometrical features and in Iraqi environmental circumstances, a numerical and experimental investigation of a solar chimney was carried out the study that dealt with an important aspect, which is to increase the surface area of the absorbent plate while maintaining the outer dimensions and limits by using three model of absorber surface (flat plate, Triangular Vgrooved corrugated plate and trapezoidal corrugated absorber plate). the work was carried out using a single vertical solar chimney of a single room has a volume 27m3 modeling 1m3 placed on the southern wall of wooden chamber having a size of (1 × 1 ×1) m and absorber plate (0.9×0.99) m. In addition to studying the effect of the air gap width (0.1, 0.2) m on the test model with all absorber plate are used at different inclination angles inward (0°,5°,10° and 15°) the test model. All variable was taken with varying solar radiation intensity (150,250,350,450,550 and 700) W/m2 along the day time. Numerical simulation of the test models using the Ansys Fluent program V18.1 to solve the governing continuity, momentum and energy equations with a standard (k-ε)standard turbulence model associated with laws of the wall along solid boundaries were solved numerically, Experimental and Theoretical results of the present study show that the optimum model of the test absorber plates with air gap width and inclination angle according to Air change per hour (ACH) calculation is Triangular V-grooved absorber plate with air gap width 0.2m and inclination angle 10°. For this inclination angle and air gap width at I700 W/m2 the ACH is about 10 % higher than model1 (flat absorber plate) and more than model3(trapezoidal plate) by 17%.

An Experimental Investigation of the Efficacy of Lawyers' Letters

2002 ◽  
Vol 21 (1) ◽  
pp. 79-93 ◽  
Author(s):  
Jack L. Krogstad ◽  
Mark H. Taylor ◽  
Maribeth J. Stock
Keyword(s):  
Experimental Study ◽  
Experimental Investigation ◽  
Lower Bound ◽  
Financial Statements ◽  
Law Students ◽  
Potential Loss

This experimental study investigates the efficacy of lawyers' letters in providing auditors with corroborating evidence about litigation contingencies. Fifty second- and third-year law students indicate their willingness to provide auditors with estimates of the likelihoods of unfavorable outcomes and potential damages for two realistic litigation cases. The findings indicate that (1) the potential loss of attorney-client privilege and (2) likelihoods of unfavorable litigation outcomes that approach auditors' lower bound for accrual both may inhibit lawyers' responses to auditors. Overall, these findings raise doubts about the efficacy of this widely utilized auditing procedure and lead to concerns about whether litigation contingencies and corresponding losses may be underreported in financial statements.

Experimental Investigation of Microcutting Mechanisms in Marble Grinding

2009 ◽  
Vol 131 (6) ◽  
Author(s):  
LJ. Tanovic ◽  
P. Bojanic ◽  
R. Puzovic ◽  
S. Klimenko
Keyword(s):  
Experimental Study ◽  
Experimental Investigation ◽  
Cutting Force ◽  
Surface Finish ◽  
Normal Component ◽  
Natural Material ◽  
Grinding Process ◽  
Force Component ◽  
Diamond Grain

This paper offers an experimental study of the microcutting mechanisms in marble grinding to aid the optimization of the marble grinding process. The necessity for investigating these mechanisms is dictated by the increased use of marble in many applications and the fact that grinding and polishing processes are the dominant technologies used to meet surface finish requirements in this natural material. The experiments are aimed at the determination of the normal component of the cutting force and of the grain traces in microcutting with a single diamond grain. The investigations carried out make provisions for establishing critical grain penetration and cutting depths and allow the prediction of the normal cutting force component as a function of grain penetration speed and depth.

Experimental Study on Sand and Cement Replacement by Termite Mound Soil

2019 ◽  
pp. 279-287
Author(s):  
Harish R ◽  
Ramesh S ◽  
Tharani A ◽  
Mageshkumar P
Keyword(s):  
Experimental Study ◽  
Experimental Investigation ◽  
Compressive Strength ◽  
Natural Environment ◽  
Fine Aggregate ◽  
Test Results ◽  
Termite Mound ◽  
Cement Concrete ◽  
Cement Ratio ◽  
Compressive Strength Of Concrete

This paper presents the results of an experimental investigation of the compressive strength of concrete cubes containing termite mound soil. The specimens were cast using M20 grade of concrete. Two mix ratios for replacement of sand and cement are of 1:1.7:2.7 and 1:1.5:2.5 (cement: sand: aggregate) with water- cement ratio of 0.45 and varying combination of termite mound soil in equal amount ranging from 30% and 40% replacing fine aggregate (sand) and cement from 10%,15%,20% were used. A total of 27 cubes, 18 cylinders and 6 beams were cast by replacing fine aggregate, specimens were cured in water for 7,14 and 28 days. The test results showed that the compressive strength of the concrete cubes increases with age and decreases with increasing percentage replacement of cement and increases with increasing the replacement of sand with termite mound soil cured in water. The study concluded that termite mound cement concrete is adequate to use for construction purposes in natural environment.

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